As the network technologies advance rapidly nowadays, the verification code mechanism that allows a user to read data safely has become indispensable.
The Completely Automated Public Turing test to tell Computers and Humans Apart (CAPTCHA) mechanism is generally known as the verification code mechanism. Through the CAPTCHA mechanism, a system, a terminal device or the like can tell whether a current user is a machine or a human being.
The current verification systems mainly employ combinations of letters, and specifically, the verification procedure is accomplished by a human being who identifies a combination of letters and then inputs the same combination of letters. However, the verification codes generated by use of combinations of letters are very uninteresting and complicated for the user.
Accordingly, an urgent need exists in the art to provide a verification system that is interesting and meaningful to the user.